Oil composition and process of retardment developing of rancidity therein



No Drawing.

Patented 1 July 3, 192,8.

UNITED s r WALTER I BALDSIEFEN, OF PARLIN, NEW JERSEY, ANI) THOMASHUNTON ROGERS, OF WILMINGTON, DELAWARE, ASSIGNORS T0 E. I. DU PONT DENEIIIOUBS & COM- EPANY, OF WILMINGTON, DELAWARE, A CORPORATION OFDELAWARE.

OIL COMPOSITION AND PROCESS OF This invention relates to coatingcompositions containing an unsaturated fatty oil and arancidity-retarder for said oil comprising an amine, particularly anaromatic amine, and includes also a process of re tarding thedevelopment of rancidity in oils which have a tendency to become rancid.

The chief object of our invention is to improve upon nitrocellulose dopecompos1- tions for use in coating of fabrics, paper, split leathers, andin general for leather substitute uses. The invention includes a composition including a base material, a sub stance containing a fatty acidradical and having a tendency to become rancid, and, an aromatic aminehaving a volatility adapting it to remain substantially permanently inthe composition.

It has been customary for many years to use vegetable oils as softenersfor pyroxylin composltions. For example, castor oil is very generallyused in the surface film of artificial leather, and either castor oil orblown rapeseed oil is used in most of the dope applied to split leather.It is noteworthy that the oils used for this purpose belong in the classof unsaturated glycerides, and it is a well-known fact that none of thesaturated glycerides is a liquid at ordinary temperature.

The most serious objection to the use of vegetable oils as softeners ofpyroxylin is their tendency to become rancid. The de-. velopment ofrancidity in vegetable oils and fats has been made the subject of agreat deal of study, and a great many contradictory conclusions havebeen drawn. There-' sults of our experiments, however, agree in the mainwith those of the Bureau of Animal Industry, at Washington, reported byRobert H. Kerr in an article published in the July 1921 number of theCotton Oil Press. Mr. Kerr states that it is practically certain thatonly glycerides of unsaturated acids are concerned in the development ofrancidity. It is important to note, therefore, that the oils which mustbe used as softeners for pyroxylin are necessarily the oils which aremost liable to develop rancidity.

Extensive experiments have confirmed us RETARDMENT nnvnnorme on moron!THEREIN.

Application filed. March 9, 1922. Serial No. 542,461.

inthe opinion that oxidation by air is the prmcipal cause of ranciditydevelopment by the oil,-that bacterial and enzymic action play no part,and that the development of rancldity is accelerated by the action ofheat and light, especially the shorterv wave powerful than, for example,aniline. This difference in the retarding effects of different aminesmay probably be accounted for in part by the differences in thevolatilities of the amines, the simple amines, such as ani line and manyof the aliphatic amines, be-

ing so volatile that they quickly escape from the composition in whichthey have been incorporated. In preferable accordance with our inventionwe use amines which are relatively non-volatile, that is are of such lowvolatility that they will remain in the composition substantiallypermanently.

Of the aliphatic amines, we have found that urea has a substantialrancidity-retarding effect, although not as powerful in this respect assome of the aromatic amines.

The invention may be illustrated by the following example A series ofnitrocellulose films was made up from three compositions containingabout sixteen ounces of nitrocellulose, of suitable viscosity, pergallon of solvent mixture composed of twenty parts denatured ethylalcohol (formula containing one-half gallon benzene per 100 gallonsethyl alcohol 95% by volume), fifty parts benzene, and thirty partsethyl acetate, together with twenty four ounces of castor oil. To onecomposition, no addition-was made; to the other two com ositions aproximately 0.08 of an ounce o urea and iphen "lamine, respectively, wasadded or approximately 0.5% of urea or diphenylamine based on thenitrocellulose used. Films were poured on glass plates using the abovethree dope compositions and portions of the three films were subjectedto storage at 65 C. in the dark in tightly stoppered bottles. Dailytests of the samples were made b smelling with the result that thepyroxylin fi in without addition developed rancidity in two days; thefilmcontaining urea did not become rancid until five days, while thefilm containing diphenylamine did not become rancid until ten days.

In other tests, portions of the samples were exposed in closed bottlesto sunlight; the film without additions turned'rancid in thirty days;the film with 0.5% urea turned rancid in the same time, while the filmcontaining 0.5% diphenylamine did not turn the following ex rancid untilforty-three days.

Rancidity tests of nitrocellulose coated fabrics containing vegetable.oils, together with 'pi ments, lakes and dyes to give desired coforshade, have shown that the presence of the amine retards the developmentof rancidity in a similar manner in which it retards ranciditydevelopment when present in the clear film without addition of pigmentor coloring matters.

The relative retarding powers of various amines in oil-nitrocellulosefilms is shown in the Table I. Thepercenta of amine is based on the oilcontent, am the test is for rancidity development at 65 C. in the dark.The plus sign indicates that the test film had not become rancid at theend of the period noted.

Table I.

Per cent.

ppppoeeao 8888 The eflicacy of diphenylamine is shown'by r1ments:

Tests were ma e on films composed of nitrocellulose and castor oil inthe ratio of one part of the former to 2.1 arts of the latter. Thesolvent mixture u consisted of parts benzol, 20 parts eth 1 acetate, and20 parts ethyl alcohol, and t e diphen lamine was added in the form ofan alcoho ic solution. The films were prepared by pouring the solutionon glass, an stripphing after the solvent had evaporated. ey were storedin closed glass bottles in an oven kept at (3., and were observed everyday for the development of rancidity. The following results wereobtained, the percentages of diphenylamine being based on the oil con-The retarding efi'ect of the amines is not limited to compositionscontaining nitrocellulose in addition to the vegetable oil, but isobtained with any vegetable oil composition. For example,,castor oilexposed on'filter paper at an elevated temperature develops rancidity ina few da s, and this development of rancidit is mar edly retarded b theaddition to t e oil of one percent of 'phenylamine.

Although -secondary aromatic amines have been exemplified above only bdiphenylamine and butyl-aniline, it wil be understood that otherrelatively non-volatile secondary amines, such as ditolylamine andamyl-aniline, may be used. Also various nitro-arylamines and aromaticamino-carboxylic acids other than those specified above may be usedprovided they are compatible with other constituents of the compositionin which their rancidity retarding action is desired.

-In making the coating compositions that are to be used in themanufacture of artificial leather, in connection with which ourinvention has especial utility, it is customary to grind the pigment ina small amount of oil and subse uently mix it with the bulk of the oiland nitrocellulose .dissolved in a suitable solvent mixture suchasdenatured ethyl alcohol, benzene, and ethyl acetate or acetone. Thearomatic amine retarder may 1. A composition of matter comprising an oilhaving a tendency a diarylamine.

2. A composition of matter comprising an oil having a tendency to becomerancid and more than 0.20% of diphenylamine based upon the amount of oilpresent.

to become rancid and 3. A composition of matter comprising anunsaturated ve etable oil and diphenylamine.

4. A composltion of matter comprising nitrocellulose, a vegetable oil,and an aromatic amine.

5. A composition of matter comprisin nitrocellulose, a vegetable oil,and a relatlvely non-volatile secondary aromatic amine having avolatility adapting it to remain substantially permanently in thecomposition.

6. A composition of matter comprisingnitrocellulose, a vegetable oil,and a diarylamine.

7 A composition of matter comprising nitrocellulose, a vegetable oil,and diphenylamine.

8. A composition of matter comprising nitrocellulose, a vegetable oil,and more than 0.20% of diphenylamine based upon the amount of oilresent.

9. A composltion of matter comprising nitrocellulose, castor oil, and anaromatic amine.

10. A composition of matter comprising nitrocellulose, castor oil, and arelatively non-volatile secondary amine having a volatility adapting itto remain substantially permanently in the com osition.

11. A composition 0 matter comprising nitrocellulose, castor oil, and adiarylamine.

12. A composition of matter comprising nitrocellulose, castor oil, anddiphenylamine.

13. A composition of matter comprising nitrocellulose, castor oil, andmore than 0.20% of diphenylamine based upon the amount of oil present.

14. A coating composition for use in the manufacture of artificialleather containing nitrocellulose, a softener therefor comprising anunsaturated glyceride, and a relatively non-volatile aromatic aminehaving a volatility adapting it to remain substantially permanently inthe composition adapted toretard the development of rancidity in saidglyceride.

15. A coating composition for use in the manufacture of artificialleather containing nitrocellulose, a softener therefor comprising anunsaturated glyceride, a pigment, and a relatively non-volatile aromaticamine having a volatility adapting it to remain substantiallypermanently in the composition adapted to retard the development ofrancidity in said glyceride.

16. A coating composition for use in the manufacture of artificialleather containing nitrocellulose, a softener therefor comprising anunsaturated glyceride, a pigment, and

between 0.25 and 4% of diphenylamine ing an unsaturated glyceride whichcomprises subjecting said composition to the continued action ofdiphenylamine.

21. The process of retarding the development of rancidity in acomposition containing nitrocellulose and castor oil which comprisessubjecting said composition .to the continued action of an aromaticamino.

22. The 'process of retarding the development of rancidity in acomposition containing nitrocellulose and castor oil which com prisessubjecting said composition to the continued action of diphenylamine. I

23. A composition of matter comprising a solution, in a volatilesolvent, of nitrocellulose, an oil having a tendency to bc come rancid,and a relatively non-volatile aromatic amine having a volatilityadapting it to remain substantially permanently in the composition.

21. A composition of matter comprising a solution, in a volatilesolvent, of nitrocellulose, castor oil, and diphenylamine.

25. A composition for use in the manufacture of artificial leathercontaining nitrocellulose, an oil having the tendency to become rancid,and diphenylamine.

26. A composition for use in the manufacture of artificial leathercontaining nitrocellulose, castor oil and diphenylamine.

27. A composition of matter comprising a base material, a substancecontaining a fatty acid radical and having a tendency to become rancid,and diphenylamine.

28. A composition of matter comprising a substance containing a fattyacid radical and having a tendency to become rancid, and diphenylamine.

In testimony whereof we atfix our signatures.

WALTER D. BALDSIEFEN. THOMAS HUNTON ROGERS CERTIFLGATE 0F CORRECTION.

Patent No. 1,675,631. Grant ed m 3, 1928, m

WALTER 1). BALDSlEFEN ET -L. It is hereby certified that error appearsin the above numbered patent requiring correction as follows: Inthegrant and in the heading to the printed specification, title ofinvention, for the words "Retardment Developing" read"RetardingDevelopment"; and that the said LettersWatent should beread-with this correction therein that the same may conform to therecord of the case in the Patent Office.

Signed and sealed this 14th dny of August, A. D. 1928.

. M. .J. Moore,

(Seal) I Acting Commissioner of Patents.

